For determining a position and/or a rotation direction of a transmitting object, such as a permanent magnet, angular sensors on the basis of Hall probes and/or on the basis of magnetic field probes are employed. To this end, several Hall probes are placed in the corners on a chip. If the transmitting object and/or the permanent magnet is rotated above the chip, the Hall probes arranged on the chip each detect a different field and are capable of calculating the angular position of the magnet on the basis of the detected fields. Since the Hall probes depend on detecting the inhomogeneity of the magnetic field, the Hall probes are arranged at great distance from each other on the chip.
By the arrangement of the Hall probes at great distance from each other, however, a bad or unfavorable matching results, so that the Hall probes have deviations from each other in their magnetic sensitivities. Since a relationship of two magnetic fields present at the respective probe locations is determined in the calculation of an angle, angle errors may develop as a result of the variation in magnetic sensitivity and of the unfavorable matching. During calibration of an angular sensor, one-time mismatches, which remain constant, of the Hall probes or probes can indeed be determined, and the disturbing quantities measured indeed be filed, e.g., in an EEPROM (electrically erasable programmable read-only memory), wherein the mismatches and/or disturbing quantities can be eliminated by downstream digital signal processing when employing the Hall probe arrangement.
But if a mismatch of the probes or Hall sensors changes over the life and/or operation of the Hall probe arrangement, an error can occur as a result of the varying magnetic sensitivities of the Hall probes that cannot be eliminated. The most common causes for a drift of the magnetic sensitivity of the Hall probes over their lives consist in a changing mechanical stress at the Hall probe arrangement or a changing temperature at the Hall probe arrangement. It is not the absolute values of a stress or a mechanical stress at the respective Hall probes on the chip or a temperature at the respective Hall probes on the chip that are of particular importance for a life drift of the magnetic sensitivity of the Hall probes, but a difference in the mechanical stress at the respective Hall probes changing over the on-time or life of the Hall probe arrangement or a changing difference in the temperatures at the respective Hall probes.